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Fruits and vegetables are some of the healthiest foods for dog owners — but what about dogs?
In many cases, the benefits of these ultra-healthy “people foods” cross over between species, affecting both humans and canines positively.
In some cases, various factors turn things sour. When it comes to grapes, humans can eat them with no worries, but dogs should never eat them due to toxicity.
Grapes are one of the most dangerous human foods for dogs due to toxicity, the cause of which is largely unknown.
No amount of grapes nor variety of grapes is conclusively for dogs. To help you learn more about why that may be and get a deeper understanding of this issue, today’s Spot Pet Insurance guide lays out all the details!
Grapes are part of the true berry family. Other fruits in this group include blueberries, cranberries, tomatoes, bananas, and peppers. Despite common belief, strawberries, blackberries, and raspberries are not technically true berries.
Thankfully, for our furry friends, grapes are the only members of the true berry family that are dangerous to dogs, so we can still feed them blueberries, cranberries, and other true berries (excluding spicy peppers, for separate reasons). Tomatoes can also be toxic in exceptionally large quantities, especially if your dog eats the green parts of the plant.
There are many different types of grapes, including seedless varieties, large and small species, and some with different colors, but all different types of grapes share the same overarching problem in that they are toxic to dogs. No grape is entirely safe for dogs.
You might be wondering if dried grapes are a safe alternative to the juicy fruits they once came from. However, raisins, which are just dried grapes, are equally dangerous.
No, dogs cannot safely consume grapes — which holds true for all dog breeds. If your dog ate grapes, make sure to call a pet poison helpline like the ASPCA Animal Poison Control Center and your vet immediately.
This may be surprising since grapes are quite healthy for humans. Like many fruits, grapes are packed full of nutrition that humans need for vital functions.
For example, antioxidants are plentiful in grapes and help humans resist the effects of aging by fighting against free radicals. Antioxidants also have anti-inflammatory properties and help maintain a healthy heart, brain, and nervous system.
Dogs need antioxidants just like we do, and they also need plenty of the vitamins that are abundant in these berries. Vitamins B1, B2, and B6, as well as vitamin C, vitamin K, and vitamin E, are all provided by grapes and would normally be of great health benefit to dogs.
Further, grapes are excellent sources of fiber and certain vital minerals, such as copper and manganese.
So with all benefits, why aren’t grapes healthy for our canine friends? The nutrients involved are vital for dogs, and dogs can digest them as normal, unlike cats, who are obligate carnivores and can’t take full advantage of plant foods to benefit from their nutrients.
The reason grapes are never safe or healthy for dogs comes down to one simple, unavoidable factor: poison.
For all the positive qualities of grapes, it only takes one quality to make them deadly to dogs.
Grapes are poisonous, but scientists have yet to pinpoint exactly why. Some theories have suggested that the inability of dogs to metabolize certain substances in grapes (tannins, flavonoids, and monosaccharides) could be related, but these theories have never been proven.
The leading theory at this time has only been explored in the last few years. This theory suggests that grapes are poisonous to dogs because they contain something called tartaric acid. Tartaric acid is no problem for us humans but poses a devastating danger to our dogs.
Tartaric acid isn’t the only danger of grapes – they are also a choking hazard. In a strange twist of irony, this danger could actually provide a chance to save your dog from consuming a grape (and consequently becoming poisoned), but it is still a serious point of concern.
In any case, pet parents must keep grapes as far away from their dogs as possible. Dogs can be mischievous and love to sneak bites of human food when humans aren’t looking, so even grapes left out around the house or brought on a picnic with your dog could be a danger.
Let’s break down the exact reasons grapes are dangerous in more detail.
The poisonous quality of grapes was totally unknown until only very recently. In a recent issue of the Journal of the American Veterinary Medical Association, a group of veterinarians presented a case that tartaric acid is likely the toxic agent responsible for grapes being so poisonous to dogs.
It wasn’t a case of grape poisoning that led to this discovery at all, but a case of poisoning caused by homemade playdough.
The American Society for the Prevention of Cruelty to Animals Animal Poison Control Center was called into the case. They realized the link after ruling out the typical causes of playdough poisoning and realizing that tartaric acid (which is found in high concentrations in grapes but few other sources) was also present here.
In past studies, tartaric acid wasn’t considered the source of adverse reactions in dogs because it is so safe for humans and most other animals used in studies, such as mice.
Thanks to the diligent efforts of a few veterinarians and scientists, we now know that tartaric acid poisoning is almost certainly what makes grapes dangerous for dogs.
Research is ongoing but continually links grape poisoning to tartaric acid (and, by extension, potassium bitartrate), which is also present in cases involving homemade playdough (made with cream of tartar) and tamarind, a type of tree bearing tropical fruit.
The veterinary science community is working hard to understand how grapes poison dogs, why, and if there is any way to minimize risks.
Some studies suggest that perhaps certain grapes are less dangerous, but the factors involved can vary so widely that it is still the consensus to avoid all grapes in any quantity.
The toxicity of grapes is the primary danger of this fruit. If even a single grape is ingested by your dog, it could be fatal. However, there are also dangers present before the grape ever reaches your dog’s stomach.
Grapes can be a serious choking hazard, especially for small dogs. The size, smooth skin, and semi-tough nature of grapes can make them easy to accidentally swallow and difficult to chew for certain dogs.
Are all grapes and grape products poisonous to dogs?
When it comes to fresh grapes, there’s an impressive amount of variety. The most obvious distinction is between red and green grapes. Additionally, some types of grapes are seedless, while others are seeded. There are also organic and non-organic grapes, and all varieties can be commercially grown or homegrown.
However, dogs have been poisoned by grapes of all varieties. This across-the-board evidence means that it’s impossible to say one kind of grape is safe compared to another.
Dogs have even been poisoned by peeled grapes, so removing the skin is not a safe method for feeding grapes to your dog. Cooked grapes still have the same toxic effect as well.
It is potentially possible that different species of grapes could be more or less poisonous, and the differences could even change across different stages of ripeness or across individual grapes or harvests.
Since poisoning has occurred in all varieties, no consistent, safe ruling can be given to any type of grape.
Raisins and currants, like fresh grapes, are dangerous in all their varieties.
Once again, various factors could affect toxicity levels in any individual group. Still, it’s impossible to predict toxicity based on these factors since no consistent pattern has been identified.
Currants, particularly the Zante currant (which is technically a dried Corinth grape), are also unsafe.
Raisins are particularly dangerous compared to fresh grapes because they can so easily slip under our radar. Raisins are frequently included in mixed human food items such as salads, trail mix, cookies, bagels, cakes, breads, granola bars, cereal, and even some casseroles and meat dishes.
We humans may love our raisins, and there’s no reason you can’t enjoy them while you share your home with furry family members. However, it is essential to your responsibility as a caregiver for a dog that you keep raisins safely out of reach.
If you want to give your dog dried fruits, consider dried cranberries instead. Cranberries are safe and beneficial for your dogs in very small quantities.
The consensus regarding solid grape consumption is resounding, but the consensus regarding grape juice (and wine from grapes) is a little fuzzier.
The safest and most widely held stance is that grape juice and grape wine, like solid grapes, should never be given to dogs in any amount.
On the other hand, some sources also claim that grape juice, wine, and similar grape products are potentially safe for dogs due to a lack of clear evidence that they are toxic.
Ultimately, the cautious approach is likely the best approach for pet parents simply because of the large number of unknowns.
Even with ongoing research that points to tartaric acid as the toxic agent in grapes, we don’t have enough information. That means we can’t make conclusive statements regarding why grapes are poisonous and in exactly what forms they may be, which means grape juice can’t truly be called a safe drink for dogs.
You might wonder if grape juice that isn’t made from fresh grapes is safe, but these recipes often use xylitol, which can be lethally toxic for dogs and must be avoided as severely as grapes, if not more so.
Alcohol, as found in grape wines, is also unhealthy for dogs and should be avoided. Even small amounts of alcohol can cause alcohol poisoning, which can vary in severity on an individual basis.
Grape jelly is a similar story to grape juice. There is some disagreement amongst various groups as to whether grape jelly is toxic. However, you’re best off avoiding it until we have a conclusive answer.
As we learn more about grape poisoning through ongoing research, answers may hopefully become more clear. Until that time, most pet parents will be best served by taking a safe approach and avoiding grape jelly when it comes to their dog’s diet and snacks.
Jelly almost always contains high amounts of sugar or sugar substitutes like xylitol, both of which should be kept away from dogs.
The natural partner-in-crime for jelly, peanut butter, happens to be a favorite snack for dogs that is safe and even healthy for dogs, in very limited quantities! Just be wary that any peanut butter you use doesn’t contain xylitol.
If you’re whipping up some morning toast or a sandwich for your lunch and you want to let your dog have a lick, give them some peanut butter, but steer clear of grape jelly (or any kind of jelly, for that matter).
Can dogs eat grapes in certain quantities without poisoning?
The answer once again is full of unknowns. In some cases, a single grape has been deadly for dogs. In other cases, dogs have eaten entire bags of grapes or raisins and survived to tell the tale.
There is ultimately no rule regarding what amount of grapes is dangerous. It can vary on a case-by-case basis.
Some dogs are more sensitive to grapes than others. There is no sign that size, breed, gender, age, or underlying health conditions affect sensitivity levels. A small dog with a weak immune system could show little to no reaction, while a large and generally healthy dog might develop severe symptoms more quickly than most. It is genuinely impossible to predict.
Because of these unknowns, the only safe way to proceed is to avoid grapes entirely for your dog. With so much at stake, it is never worth giving your dog a grape snack – not even a little bite.
If your dog does consume grapes, they will likely suffer grape poisoning. There’s no way to know exactly how your dog will react to grapes until it happens, and they might even react differently if they happen to have two different incidents with grapes in their lifetime.
The most important responsibility you have as a pet parent is to seek treatment immediately. If your dog happens to consume even a single grape, you should not wait and see how they react. Contact medical help as soon as possible.
Unlike some other toxic foods or cases of food sensitivity, the symptoms of grape poisoning may not simply fade away after a bit of time.
The symptoms may not become serious, but it is also possible your dog could suffer acute kidney (renal) failure, which is often fatal. Grape poisoning left untreated has a much worse prognosis than if promptly treated.
Your pet parent responsibilities start with knowing the signs of grape poisoning. You may not see your dog snatch a grape, so you may have to deduce what’s going on if your dog becomes sick and there is any chance a grape or raisin was involved.
Knowing the signs could save your dog’s life. If there is even one symptom along with the possibility your dog ate a grape, grape product, or raisin, you shouldn’t hesitate to seek professional help.
Symptoms of grape poisoning often develop within 24-72 hours of ingestion of a toxic dose. In acute cases, symptoms develop more swiftly and can be more severe, making it necessary for a pet owner to race their dog to the vet.
*These symptoms may indicate severe kidney failure.
Because the symptoms of grape poisoning crossover with the symptoms of numerous other conditions, it’s essential to seek a professional diagnosis without delay.
The most serious possibility in a case of grape poisoning is acute kidney (renal) failure.
When the kidney becomes damaged, the chances of a poor prognosis for survival start to increase. This is a large part of why prompt treatment is so important. If left untreated, kidney problems are even more dangerous and life-threatening.
The kidney is a vital organ for dogs that maintains blood pressure and helps the body metabolize and process waste, among other functions.
The kidney can be damaged by any number of toxins, including over-the-counter products, medications, and substances found around your house, such as cleaning supplies or antifreeze. In the case of foods, grapes are one of the biggest culprits of kidney damage.
Kidney damage should be professionally assessed and treated. Potential grape poisoning is not like mild food sensitivities that could be diagnosed and treated at home.
Professional veterinary treatment typically involves hospitalization, ideally as soon as possible after ingestion.
The most important thing treatment aims to accomplish is protecting the kidney since kidney damage is the most dangerous aspect of grape poisoning.
Decontamination (induced vomiting or other techniques) is typically the first step (but should only be done professionally). Preventing further absorption of toxins is another goal pursued in the initial stages of treatment, usually through activated charcoal.
Intravenous fluid and medications can help stabilize your dog and prevent further damage to the kidney and surrounding vital organs.
Ultimately, the exact steps needed to treat your dog will vary widely based on how long it has been since your dog ingested the grapes, how many grapes they ate, and numerous other factors.
The length of treatment can also vary. Often hospitalization may be needed for a few days, as medical professionals support your dog’s vital functions and monitor their kidneys to determine if further treatment is needed or if they are safe to return home.
Prognosis can range from excellent to poor, depending on a number of factors.
Quantity of toxic substance consumed, time until treatment, damage to the kidney before treatment, and response to treatment play a significant role in determining prognosis.
Thankfully, dogs who receive immediate treatment after consuming only a small amount of grapes or raisins have an excellent prognosis – meaning their chance of recovery is very high.
Prognosis becomes worse once kidney damage occurs. A complete lack of urination can also be a sign of a worsening prognosis. In these cases, death may be likely, since kidney damage is typically permanent since the organ is not built to repair itself.
As a pet parent, the best thing you can do is be diligent in watching for signs and never hesitate (even when in doubt) to contact professional help from a poison control center or veterinary professionals.
Grapes could be dangerous in any amount, so there is never a good reason to feed your dog grapes. Instead, you could turn to any number of positive alternative snacks.
Even amongst the true berry family, grapes have numerous safe siblings, including blueberries, cranberries, bananas, and bell peppers.
Other excellent fruits for dogs include:
Remember that grapes and raisins are never fruits you should feed your dog. These have particular enzymes in them that are toxic to dogs—avoid grapes and raisins around your dog like you avoid chocolate! We have compiled a big list of all the fruits your dogs should eat here.
You can also mix fruits or vegetables with plain Greek yogurt (made with no artificial ingredients) for a tasty pup parfait!
With any human food you want to introduce to your dog, you should first talk to a trusted veterinarian. Most human foods come with some caveats, mainly that they should only be given to dogs in small quantities and should contain no artificial ingredients.
You can also learn more about pet insurance through our FAQs.
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